Douglas was born on 3 August 1901 in Frensham (Farnham) Surrey. He was the fourth child of Fred and Mary Ann (née Thorne) Lewis, and also had three sisters and two brothers. He is the only sibling to have his mother’s maiden name Thorne. In 1901 the family were living in the area of Frensham, Surrey before moving on to Brighton, Sussex, where his younger sister Frances Olivia was born in 1909. The address in 1918 for his Next Of Kin (Mother) is also Brighton. Douglas left Brighton to join the Royal Navy in March 1917.

On 7 March 1917 Douglas climbed a gangway of HMS IMPREGNABLE in Devonport dockyard for the first time to spend 12 weeks of basic seamanship training before a transfer to HMS GANGES in Shotley, Suffolk, on 9 June 1917. On 15 August he qualified for telegraphist and was made a Boy Telegraphist, then continued his training until the 6 December, when he moved to HMS VICTORY l  in Portsmouth for a further 2 months training. On 9 January 1918 he moved across the water on draft to a ship’s company billet in HMS DOLPHIN for two months until a draft dated 20 March 1918 had him travel North to HMS TITANIA ,the depot ship for the 11th Submarine Flotilla, moored in Blyth harbour, Northumberland.

HMS G7 was transferred from HMS LUCIA of the 10th Flotilla to HMS TITANIA of the  11th Flotilla in September 1918. At 0645  on 21 October G7 cast off from TITANIA for a patrol in the North Sea. She acknowledged a patrol area change on the 23 October, the last contact with G7.

In 2015 a submarine like silhouette was recorded on a side scan sonar trace in an area known as Farne Deep which later proved to be that of G7. Visual inspection of the wreck site by divers indicate she was heading home on the surface when a catastrophic incident occurred. The geographical position would give the date of 31 October as the most probable day of the incident. There were no survivors from her 31 crew members, one of which was Boy Telegraphist Douglas Thorne Lewis who was 17 years and 3 months old.

He is commemorated on the Portsmouth Naval Memorial on Panel 29.